Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

public class _815 {
	public static void main(String[] args) {
		FastReader fr = new FastReader();

		int n = fr.nextInt();
		int m = fr.nextInt();

		int[] r1 = new int[n];
		int[] c1 = new int[m];

		int[] r2 = new int[n];
		int[] c2 = new int[m];

		int sum1 = 0;
		int sum2 = 0;

		int sum = 0;

		int[][] a = new int[n][m];

		int res1 = 0;
		int res2 = 0;

		for(int i = 0; i < n; i++){
			for(int j = 0; j < m; j++){
				int x = fr.nextInt();
				sum += x;
				a[i][j] = x;
			}
		}

		// Meth1
		for(int i = 0; i < n; i++){
			for(int j = 0; j < m; j++){
				int x = a[i][j];
				if(j == 0 || x < r1[i]){
					r1[i] = x;
				}

			}
		}

		for(int j = 0; j < m; j++){
			c1[j] = 500;
			for(int i = 0; i < n; i++){
				int x = a[i][j] - r1[i];
				if(x < c1[j]){
					c1[j] = x;
				}
			}
		}

		for(int i = 0; i < n; i++){
			res1 += r1[i];
			sum1 += r1[i] * m;
		}

		for(int j = 0; j < m; j++){
			res1 += c1[j];
			sum1 += c1[j] * n;
		}

		// Meth2
		for(int j = 0; j < m; j++){
			for(int i = 0; i < n; i++){
				int x = a[i][j];
				if(i ==0 || x < c2[j]){
					c2[j] = x;
				}
			}
		}

		for(int i = 0; i < n; i++){
			r2[i] = 500;
			for(int j = 0; j < m; j++){
				int x = a[i][j] - c2[j];
				if(x < r2[i]){
					r2[i] = x;
				}

			}
		}

		for(int i = 0; i < n; i++){
			res2 += r2[i];
			sum2 += r2[i] * m;
		}

		for(int j = 0; j < m; j++){
			res2 += c2[j];
			sum2 += c2[j] * n;
		}
		if(sum1 == sum || sum2 == sum){
			int res;
			int[] r;
			int[] c;
			if(res1 <= res2 && sum1 == sum){
				res = res1;
				r = r1;
				c = c1;
			}else{
				res = res2;
				r = r2;
				c = c2;
			}
			System.out.println(res);
			for(int i = 0; i < n; i++){
				for(int j = 0; j < r[i]; j++){
					System.out.println("row " + (i+1));
				}
			}

			for(int i = 0; i < m; i++){
				for(int j = 0; j < c[i]; j++){
					System.out.println("col " + (i+1));
				}
			}
		}else{
			System.out.println(-1);
		}
	}

	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			InputStreamReader inr = new InputStreamReader(System.in);
			br = new BufferedReader(inr);
		}

		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());

		}

		public long nextLong() {
			return Long.parseLong(next());
		}

		public String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

}